Strand-based laminates in absorbent articles

ABSTRACT

Absorbent articles comprising a multilayer outer cover comprising a first outer layer and a second outer layer comprising a component that exhibits at least partial elastic recovery after mechanical activation in the machine direction; an inner layer, disposed between the first outer layer and the second outer layer, the inner layer comprising elastic strands; and wherein at least one of the first outer layer and second outer layer is laminated to the inner layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 16/660,902, filed on Oct.23, 2019, which is a continuation of U.S. application Ser. No.15/185,050, filed on Jun. 17, 2016, which claims the benefit of U.S.Provisional Application No. 62/186,404, filed on Jun. 30, 2015, all ofwhich incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to stretch laminates useful forincorporation into absorbent articles.

BACKGROUND OF THE INVENTION

Infants and other incontinent individuals wear disposable absorbentarticles such as diapers to receive and contain urine and other bodyexudates. Training pants or pull-on diapers have become popular for useon children able to walk and often who are toilet training. Manydisposable pull-on garments use elastic elements secured in anelastically contractible condition in the waist and/or leg openings.Typically, in order to insure full elastic fit about the leg and thewaist such as is provided with durable undergarments, the leg openingsand waist opening are encircled at least in part with elasticized bandsof rubber or other materials positioned along the periphery of therespective opening.

Stretchable laminates structures used in the chassis of absorbentproducts and known in the art are for the great majority constructed byusing prestrained elastic materials that are adhesively bonded onto twostandard nonwoven layers. The elastic material may be, for example,strands, strips of elastic film, or tapes of elastic film. This is oftenreferred to as “live stretch”. When fully strained, the elastic-basedstructures may need to provide stretch up to 120% or to 200%, dependingon location, for example, if used in stretch back ears in taped productsor in side panels in pant products. However when used as a chassiscomponent that circles around the body and provides 360 degreeall-around stretch, 80-170% stretch can suffice. In order to achievethis amount of stretch, the elastic, such as strands or tapes of elasticfilm, must be prestrained to a higher amount before the nonwoven isbonded onto them. As the nonwovens are applied onto the prestrainedstrands, the nonwovens form gathered structures as they are forced toaccommodate the recovery of the strands. This produces an expansion ofthe laminates in the direction perpendicular to the plane defined by thestrands. The above phenomenon is often referred to as gathering orpuckering of the web. The more bonding of the strands and the webstogether, the more this constriction takes place during the recoveryprocess.

While these structures and the resulting puckering have been generallyaccepted by consumers short of alternatives, it has become clear thatfrom a performance standpoint, large amounts of puckering have anundesirable effect to the touch and feel of the final laminates. It alsomakes it very difficult to create a garment-like look when used in achassis, which is an ever more desirable feature sought by theconsumers.

From a cost standpoint, there are also several negatives: (i) as thenonwovens gather, their basis weight increases and therefore thenonwoven cost increases. For instance, for nonwoven layers applied onto150% pre-stretched strands or tapes, there is a 250% basis weightincrease of the nonwoven layers concomitant with a 250% increase incost. So 12 grams per square meter (gsm) becomes 30 gsm after gatheringwith a concomitant increase in cost; (ii) bonding nonwovens togetheralong with elastic strands or tapes strapped in between is extremelyinefficient and requires a large amount of adhesive as a lot of adhesivediffuses into the nonwoven itself and becomes ineffective. About 16-20gsm of adhesive is generally needed; (iii) printing on a nonwoven isneither easy nor cost-effective. Moreover, given the highly irregularpuckered state in the final stretch laminates, it is virtuallyimpossible to have attractive and sharply defined patterns of any kindprinted onto them.

From a process standpoint, the more elastic strands or tapes are used,the more elasticity can be imparted to the stretch laminate and/or themore finely the strands or tapes can be distributed; but the more costlythe laminate and the more complex the process becomes with a greaterrisk of strand or tape failure during construction and the issues ofprocess reliability that result from it. There is a clear tradeoffbetween a fine dispersion of lower diameter strands and the increase inthe occurrence of strand failure. Also, depositing large amounts ofadhesive is always a challenge. Finally, thermal bonding of thelaminates onto itself where seaming is needed to construct the productis difficult at high speed due to the high melting temperature of thenonwovens, and possibility of strand breakage. Thermal bonding alsoresults in creep of strands in stretched laminates, i.e. strands cominglose and retracting.

As an alternative to the kind of “live stretch” produced by strand-basedlaminates, elastic film-based laminates have also been disclosed andused in so-called “zero-strain” structures. Examples of those aredisclosed in US Patent Publications 2007/0287348 and 2008/0045917. Inthese, nonwovens may be bonded onto an elastic film and the laminate isthen subjected to an activation process that unlocks the constraintsimposed by the nonwoven and frees up the ability of the film to stretchand recover. These produce laminates structures which are very appealingfor the look and feel and are ideal when introduced as stretchableoutercovers in disposable absorbent products. However, in order for themto be effective, one might have to include high basis weight andsomewhat costly elastic films, or they might offer only a limited rangeof stretch. Even if the high level of strain is achieved via use ofhigher film basis weight, the activated laminates do not lookaesthetically appealing because of very defined corn-row likeappearance, and somewhat broken nonwoven.

In view of all these issues, it is of great interest to create adifferent technology that can impart the high levels of stretchperformance obtained in strands-based laminates, along with the processreliability and attractive final attributes of elastic film-based ones.

SUMMARY OF THE INVENTION

In one embodiment, the present invention relates generally to anabsorbent article comprising a topsheet, an outer cover, and anabsorbent core disposed between the topsheet and the outer cover,wherein the outer cover comprises a multilayer substrate. The multilayersubstrate comprises a first outer layer and a second outer layer,wherein at least one of the first or second outerlayer comprises acomponent that exhibits at least partial elastic recovery aftermechanical activation in the machine direction, and an inner layer,disposed between the first outer layer and the second outer layer,wherein the inner layer comprises elastic strands.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of the presentdisclosure, and the manner of attaining them, will become more apparentand the disclosure itself will be better understood by reference to thefollowing description of non-limiting embodiments of the disclosuretaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of an exemplary disposable pull-on garmentin a typical in-use configuration;

FIG. 2 is a perspective view of an exemplary disposable pull-on garmentin a typical in-use configuration;

FIG. 3 is a plan view of the pull-on garment in its flat uncontractedcondition showing the inner surface;

FIG. 4 a is a schematic cross section view of a first embodiment takenalong line 4-4 in FIG. 3 of an exemplary disposable pull-on garment;

FIG. 4 b is a schematic cross section view of a second embodiment takenalong line 4-4 in FIG. 3 of an exemplary disposable pull-on garment;

FIG. 4 c is a schematic cross section view of a third embodiment takenalong line 4-4 in FIG. 3 of an exemplary disposable pull-on garment;

FIG. 4 d is a schematic cross section view of a fourth embodiment takenalong line 4-4 in FIG. 3 of an exemplary disposable pull-on garment;

FIG. 4 e is a schematic cross section view of a sixth embodiment takenalong line 4-4 in FIG. 3 of an exemplary disposable pull-on garment;

FIG. 4 f is a schematic cross section view of a seventh embodiment takenalong line 4-4 in FIG. 3 of an exemplary disposable pull-on garment;

FIG. 4 g is a schematic cross section view of an eight embodiment takenalong line 4-4 in FIG. 3 of an exemplary disposable pull-on garment;

FIG. 5 is a schematic cross section view taken along line 5-5 in FIG. 3of an example of a folded outer leg cuff suitable in one embodiment ofthe invention.

FIGS. 6A-6C are schematics of inner and outer layers of one embodimentof the present invention.

FIGS. 7A-7C are schematics of assemblies of inner and outer layers ofembodiments of the present invention.

FIGS. 8A-8C are schematics of inner and outer layers of one embodimentof the present invention.

FIG. 9 is a photograph of Examples 1-4.

FIG. 10 is a graph of tensile data for Examples 1-4.

DETAILED DESCRIPTION OF THE INVENTION

Various non-limiting embodiments of the present disclosure will now bedescribed to provide an overall understanding of the principles of thestructure, function, manufacture, and use of the apparatuses and methodsdisclosed herein. One or more examples of these non-limiting embodimentsare illustrated in the accompanying drawings. Those of ordinary skill inthe art will understand that the apparatuses and methods specificallydescribed herein and illustrated in the accompanying drawings arenon-limiting example embodiments and that the scope of the variousnon-limiting embodiments of the present disclosure are defined solely bythe claims. The features illustrated or described in connection with onenon-limiting embodiment may be combined with the features of othernon-limiting embodiments. Such modifications and variations are intendedto be included within the scope of the present disclosure.

Definitions

In this description, the following terms have the following meanings:

The term “absorbent article” refers to a device that is placed againstor in proximity to a body of a wearer to absorb and contain variousexudates discharged from the body. Example absorbent articles comprisediapers, training pants, pull-on pant-type diapers (i.e., a diaperhaving a pre-formed waist opening and leg openings, such as illustratedin U.S. Pat. No. 6,120,487, issued to Ashton, on Sep. 19, 2000); beltedpants (for example, U.S. Ser. Nos. 13/893,604, 13/764,990, 13/893,735,and 13/893,405), refastenable diapers, incontinence briefs andundergarments, diaper holders and liners, feminine hygiene garments,panty liners, and absorbent inserts, for example.

“Activatable nonwoven” refers specifically to nonwovens that havemechanical properties that interact well with films during theactivation process. Activatable nonwovens of the present invention givetensile curves (ASTM D882-02, gauge length=5 mm, specimen width=25.4 mm,crosshead speed=2.117 mm/s, deformation direction coinciding with thatapplied during the activation process) characterized by relatively lowmaximum forces and relatively large engineering strains. Specifically,if the nonwoven's curve's maximum force point lies below 4 N/cm at anengineering strain value of greater than 100%, then, for the purposes ofthe present invention, it is deemed to be “activatable.” “Activated”refers to a material which has been mechanically deformed so as toimpart elasticity to at least a portion of the material, such as, forexample by incremental stretching. As used herein the term “activation”means any process by which tensile strain produced by intermeshing teethand grooves causes intermediate web sections to stretch or extend. Suchprocesses have been found useful in the production of many articlesincluding breathable films, stretch composites, apertured materials andtextured materials. For nonwoven webs, the stretching can cause fiberreorientation, change in fiber denier and/or cross section, a reductionin basis weight, and/or controlled fiber destruction in the intermediateweb sections. For example, a common activation method is the processknown in the art as ring rolling. U.S. Pat. Nos. 7,062,983, 6,843,134,6,830,800, 5,143,679, and 5,167,897 disclose examples of the activationprocess.

“Adhesive” refers to compositions comprising one or more thermoplasticpolymers, one or more tackifier resins, and typically a rheologymodifier or plasticizer. Adhesives contain 2% or more of a tackifierresin. An adhesive is generally used to join or bond two or morematerials together by applying it to at least one material and thenbringing it into contact with at least one other material withsufficient force and for a sufficient duration of time, that theadhesive can wet out or spread on each material to join them together(see definition of “tackifier” below).

“Adhesive-free” refers to a laminate where an adhesive is not used tobond the elastomeric member (e.g., elastomeric film) to the nonwoven ornonwovens, and therefore an adhesive is not part of the final laminatestructure.

“Adhesively bonded” or “adhesively laminated” refers to a laminatewherein an adhesive is used to bond an elastomeric member (e.g.,elastomeric film) to a nonwoven(s) or to a second elastomeric member.

“Bicomponent fiber” refers to fibers or filaments consisting of materialof two different compositions arranged across the cross-section of thefiber or filament. Each composition is typically delivered by a separateextruder to a spin pack designed to arrange the compositions intoarrangements such as sheath-core, side-by-side, segmented pie andislands-in-the-sea. The mutual arrangement of different compositions canbe beneficial in tailoring the chemical affinity between a film and anonwoven in a laminate.

“Bilaminate” refers to multilayer composite comprising a film (monolayeror multilayer) and one nonwoven, which is formed by extrusionlamination, adhesive lamination, sonic welding or pressure bonding.

“Blocking” refers to the phenomenon of a film sticking to itself or tothe opposite outer facing side of a composite laminate structure whenthe film or laminate is rolled, folded, or otherwise placed in intimatesurface to surface contact.

“Body-facing,” “inner-facing,” “outer-facing,” and “garment-facing”refer respectively to the relative location of an element or a surfaceof an element or group of elements. “Body-facing” and “inner-facing”imply the element or surface is nearer to the wearer's body during wear(i.e., closer to the wearer's body than a garment-facing surface or anouter-facing surface). “Garment-facing” and “outer-facing” imply theelement or surface is more remote from the wearer during wear (i.e.,element or surface is nearer to the wearer's garments that can be wornover the disposable absorbent article).

“Breathable” or “breathability” in reference to absorbent articles meansthat the absorbent article comprises a vapor-permeable layer orvapor-permeable multilayered structure that allows water vapor to passout of the interior of the diaper. The Water Vapor Transmission Rate(WVTR, reported in gm/m²/day), is a measure of breathability. WVTR ismeasured by the INDA/EDANA Worldwide Strategic Partners WSP 70.4 (08)standard test method.

“Comprise,” “comprising,” and “comprises” are open ended terms, eachspecifies the presence of what follows, e.g., a component, but does notpreclude the presence of other features, e.g., elements, steps,components known in the art, or disclosed herein.

“Consisting essentially of” is used herein to limit the scope of subjectmatter, such as that in a claim, to the specified materials or steps andthose that do not materially affect the basic and novel characteristicsof the subject matter.

“Crystallization rate” refers to the kinetics of crystal nucleation andgrowth from a polymer melt, as it is cooled in, and following, anextrusion lamination process. Crystallization rate reflects the route bywhich a polymer solidifies from a molten, amorphous state. DifferentialScanning Calorimetry (DSC) may be used according to ASTM D 3418 asdescribed in more detail in the Test Methods to determinecrystallization rates of polymers, polymer blends, and formulationscomprising polymers useful in films, including skin and tie layers, ofthe present invention.

As used herein “depth of engagement” (DOE) means the extent to whichintermeshing teeth and grooves of opposing activation members extendinto one another.

“Diaper” refers to an absorbent article generally worn by infants andincontinent persons about the lower torso so as to encircle the waistand legs of the wearer and that is specifically adapted to receive andcontain urinary and fecal waste. As used herein, term “diaper” alsoincludes “pants” which is defined below.

“Disposable” in reference to absorbent articles, means that theabsorbent articles are generally not intended to be laundered orotherwise restored or reused as absorbent articles (i.e., they areintended to be discarded after a single use and may be recycled,composted or otherwise discarded in an environmentally compatiblemanner).

“Disposed” refers to an element being positioned in a particular placewith regard to another element. When one group of fibers is disposed ona second group of fibers, the first and second groups of fibersgenerally form a layered, laminate structure in which at least somefibers from the first and second groups are in contact with each other.In some embodiments, individual fibers from the first and/or secondgroup at the interface between the two groups can be dispersed among thefibers of the adjacent group, thereby forming an at least partiallyintermingled, entangled fibrous region between the two groups. When apolymeric layer (for example a film), is disposed on a surface (forexample a group or layer of fibers), the polymeric layer can belaminated to or printed on the surface.

As used herein, the terms “elastic,” “elastomer,” and “elastomeric”refer to any material which when evaluated using hysteresis methoddescribed below, extend to an engineering strain of at least 50% withoutbreaking or rupturing, and is able to recover substantially to itsoriginal dimensions after the deforming force has been removed, i.e.show % set less than 30% according to hysteresis method describedherein,

“Engineering strain” is the change in length of a specimen (in thedirection of applied stress or strain) divided by the specimen'soriginal length (William D. Callister Jr., “Materials Science andEngineering: An Introduction”, 1985, John Wiley & Sons, Inc. New York,Chichester, Brisbane, Toronto, Singapore). To calculate percentengineering strain, the engineering strain is multiplied by 100.

“Ethylene rich” refers to the composition of a polymeric layer (e.g., asheath of a bicomponent fiber or a skin layer of a film) or a portion ofa layer of an EBL or nonwoven that comprises at least about 80% byweight of polyethylene (including homopolymers and co-polymers). Forexample, a sheath of a core-sheath bicomponent fiber, wherein the sheathis comprised of greater than about 80% by weight of a linear, lowdensity polyethylene, is ethylene rich.

“Extensible”, “plastic” and “extendibility” (e.g. extensible nonwoven,plastic film or extendibility of the elastomer), means the ability ofmaterial to stretch or elongate, without rupture or breakage, to atleast 130% strain, for example, as described below in the Tensile Test

“Extrusion bonded laminate (‘EBL’)” refers to a multilayer compositeformed by extruding an elastomeric extrudate directly onto at least onenonwoven at or near a nip formed between two calender rollers, such thatat least some nonwoven fibers penetrate into the soft extrudate film inorder to join the film and the nonwoven. The amount of penetration ofnonwoven into the soft extrudate may be controlled by selecting a nipgap smaller than the caliper of the nonwoven plus the film, by adjustingthe pressure of the rolls, or by other means well understood to one ofordinary skill in the art. In one embodiment, the elastomeric extrudatemay be a monolayer film comprising one or more elastomeric polymers. Inanother embodiment, the elastomeric extrudate may be a coextrudedmultilayer film with one or more outer layers and one or more innerlayers.

“Extrusion lamination” or “extrusion coating” refers to processes bywhich a film of molten polymer is extruded onto a solid substrate (e.g.,a nonwoven), in order to coat the substrate with the molten polymer filmto bond the substrate and film together.

“Joined” refers to configurations whereby an element is directly securedto another element by affixing the element directly to the other elementand to configurations whereby an element is indirectly secured toanother element by affixing the element to intermediate member(s) whichin turn are affixed to the other element. Materials may be joined by oneor more bonding processes including adhesive bonding, thermal welding,solvent welding, ultrasonic bonding, extrusion bonding, and combinationsthereof.

“Laminate” means two or more materials that are bonded to one another bymethods known in the art, e.g., adhesive bonding, thermal bonding,ultrasonic bonding.

“Liquid-permeable” (or “liquid-pervious”) and “liquid-impermeable” (or“liquid-impervious”) refer to the penetrability of materials in thecontext of the intended usage of disposable absorbent articles.Specifically, “liquid permeable” refers to a layer or a layeredstructure having pores, openings, and/or interconnected void spaces thatpermit liquid water to pass through its thickness at less than 5 mbar ofhydrostatic head (as defined by INDA 80.6-01). Conversely, “liquidimpermeable” refers to a layer or a layered structure through thethickness of which liquid water cannot pass through its thickness atless than 5 mbar of hydrostatic head (as defined by INDA 80.6-01). Alayer or a layered structure that is water-impermeable according to thisdefinition may be vapor-permeable, for example permitting transmissionof air and water vapor. Such a vapor-permeable layer or layeredstructure is commonly known in the art as “breathable.”

“Machine direction” (also “MD” or “length direction”) as applied to afilm or nonwoven material, refers to the direction that was parallel tothe direction of travel of the film or nonwoven as it was processed inthe forming apparatus. The “cross machine direction” (also “CD” or“width direction”) refers to the direction perpendicular to the machinedirection.

“Outer cover” refers to that portion of the diaper which is disposedadjacent to the garment-facing surface of the absorbent core. Outercovers have tensile properties that enable ease of the application ofthe article, as well as enabling the article to conform to the wearer'sbody. In some embodiments it may prevent the excreta and/or exudatescontained therein from soiling garments or other articles which maycontact the diaper, such as bedsheets and clothing. In theseembodiments, the outer cover may be impervious to liquids. In otherembodiments, the outer cover may be liquid pervious. Outer covers of thepresent invention may be breathable. Outer covers of the presentinvention may comprise a multilayer laminate structure, including anEBL.

“Partial Elastic Recovery” refers to amount of recovery materialexhibits upon removal of deforming force as described in the hysteresismethod herein. For example, material is extend to an engineering strainof 50% as described in the hysteresis method, and shows 20% Set afterthe deforming force has been removed, i.e. it shows 80% partial elasticrecovery according to hysteresis method described herein.

“Pant,” “training pant,” “pre-closed diaper,” “pre-fastened diaper,”“pull-on diaper,” and “pant-like garment” as used herein, refer todisposable garments having a waist opening and leg openings designed forinfant, children, or adult wearers. A pant can be configured such thatthe pant has a closed waist and leg openings prior to being donned onthe wearer, or the pant can be configured such that the waist is closedand the leg openings formed while being donned on the wearer. A pant maybe preformed by any suitable technique including, but not limited to,joining together portions of the article using refastenable and/ornon-refastenable bonds (e.g., seam, weld, adhesive, cohesive bond,fastener, etc.). A pant may be preformed anywhere along thecircumference of the article (e.g., side fastened, front waist fastened,rear waist fastened). Examples of suitable pants are disclosed in U.S.Pat. Nos. 5,246,433; 5,569,234; 6,120,487; 6,120,489; 4,940,464;5,092,861; 5,897,545; 5,957,908; and U.S. Patent Publication No.2003/0233082 A1.

“Permanent set” is the permanent deformation of a material after removalof an applied load. Permanent set is typically expressed as a percentincrease relative to the original size. It is measured as % Set asdescribed in the Hysteresis Test.

“Petrochemical” refers to an organic compound derived from petroleum,natural gas, or coal.

“Petroleum” refers to crude oil and its components of paraffinic,cycloparaffinic, and aromatic hydrocarbons. Crude oil may be obtainedfrom tar sands, bitumen fields, and oil shale.

“Plastoelastic” and “elastoplastic” as used herein are synonymous andrefer to any material that has the ability to stretch in a substantiallyplastic manner during an initial strain cycle such as the one describedin the hysteresis method below (i.e., applying a tensile force to inducestrain in the material, then removing the force allowing the material torelax), yet which exhibits substantially elastic behavior and recoveryduring subsequent strain cycles, i.e when relaxed material is subjectedto another strain cycle as per the hysteresis method below.Plastoelastic materials contain at least one plastic component and atleast one elastic component, which components can be in the form ofpolymeric fibers, polymeric layers, and/or polymeric mixtures(including, for example, bi-component fibers and polymeric blendsincluding the plastic and elastic components). Suitable plastoelasticmaterials and properties are described in U.S. 2005/0215963 and U.S.2005/0215964.

“Propylene rich” refers to the composition of a polymeric layer (e.g., asheath of a bicomponent fiber or a skin layer of a film) or a portion ofa layer of an EBL or nonwoven that comprises at least about 80% byweight of polypropylene (including homopolymers and copolymers). Forexample, a tie layer comprising 96% VISTAMAXX 6102 (16% by weight PE/84%by weight PP), is propylene rich.

“Side panel,” “front ear,” “back ear,” or “ear panel” refers to thatportion of an absorbent article which is disposed adjacent to the outercover or core or topsheet and connect a front waist edge to a back waistedge. Side panels or front/back ears have tensile properties that enableease of the application of the article, as well as enabling the articleto conform to the wearer's body. Side panels or front/back ears of thepresent invention may comprise a multilayer laminate, including an EBL.Examples of side panels that may be used in the present invention aredescribed and illustrated in EP 1150833 (referenced as ear panels).

“Skin layer” refers to an outer layer of a coextruded, multilayer filmthat acts as an outer surface of the film during its production andsubsequent processing.

“Substrate” as used herein describes a material that is primarilytwo-dimensional (i.e., in an XY plane) and whose thickness (in a Zdirection) is relatively small (i.e. 1/10 or less) in comparison to itslength (in an X direction) and width (in a Y direction). Non-limitingexamples of substrates include a web, layer or layers or fibrousmaterials, nonwovens, and films and foils, such as polymeric films ormetallic foils, for example. These materials may be used alone or maycomprise two or more layers laminated together. As such, a web is asubstrate.

“Synthetic polymer” refers to a polymer which is produced from at leastone monomer by a chemical process. A synthetic polymer is not produceddirectly by a living organism.

“Tackifier” refers to an adhesive component with a glass transitiontemperature in the range from about 70° C. to about 150° C. thatdecreases the melt viscosity of a rubbery polymer and increases therubbery polymer's glass transition temperature and decreases the rubberypolymer's entanglement density.

“Tie layer” refers to a layer of a coextruded, multilayer film that actsas an intermediary between an inner layer of the film and anothermaterial, such that the laminate strength between the inner layer andthe other material is improved (increased or decreased). The tie layer'scomposition can be adjusted to modify or optimize the chemical andphysical interactions between film and nonwoven. Tie layers of thepresent invention do not contain more than 2% of a tackifier resin, andare substantially continuous over the entire surface of the coextrudedfilm. In the present invention, it may be desirable to have a tie layerand skin layer which are compositionally identical.

“Web” means a material capable of being wound into a roll. Webs may befilms, nonwovens, laminates, apertured laminates, etc. The face of a webrefers to one of its two dimensional surfaces, as opposed to its edge.

“X-Y plane” means the plane defined by the MD and CD of a moving web orthe length.

In one embodiment, it is an object of the invention to provide auniaxially stretchable multilayer fabric or substrate consisting of acollection of prestrained elastic strands or tapes of elastic filmpositioned in between two outer layer structures. These outer layersencompass at least one prestrained elastic laminate structure made of acombination of stretchable nonwovens and/or film/nonwoven laminatestructures that are mounted onto the prestrained elastic strands whilethe outer layer is in a stretched state. The outer prestrained layersare such that at least one of them includes a component materialproviding at least partial elastic recovery after mechanical activationin the machine direction (MD), namely in the same direction as thestrands.

In some embodiments, it is further an object to create a uniaxiallystretchable multilayer fabric or substrate with a reduced amount ofgathering in at least one of the outer layers when such an outer layeris prestrained prior to bonding. The amount of gathering is controlledby the amount of prestrain applied onto at least one partiallyrecoverable outer layer relative to that of the prestrained strands. Itreplaces regions having the puckered appearance of unstrained nonwovenswith regions having the appearance and feel of an activated nonwoven.For instance, equal amount of prestraining in both the strands and thestretched outer layer will completely eliminate puckering, whereasapplying an outer layer without any prestrain would exhibit similarpuckering as seen in known nonwovens and products.

In other embodiments, an object of the invention is to allow for thereduction of the number or the size of strands by replacing a fractionof them with at least one stretchable and recoverable outer layer, theequivalence in mechanical performance dictating the balance between theactual number of strands being replaced and the stretch characteristicsof a given outer elastic layer.

It is further object of the invention to provide a stretchablemultilayer fabric or substrate with a means of tailoring its opacity andbarrier properties.

It is a further object of the invention to use a laminate split into atleast two components in the machine direction of the product to provideairflow through the multilayer structure.

It is a further object of the invention to reduce the amount of adhesivenecessary to bond all the layers of the stretchable multilayer fabric orsubstrate together by reducing the amount of adhesive that penetratesthe fiber assembly.

It is another object of the invention to provide elastomericpolyolefin-based strands that provide the option of discrete thermalbonding of the strands onto the outer layers.

It is another object of the invention to provide elastomericstyrene-based-copolymer-based strands with controlled rate of recovery.

It is another object of the invention to use thermal bonding capable ofassembling both outer layers together with the elastic strands, furtherlowering the amount of adhesive needed as well as allowing the use ofunder-bonded webs in the construction of the outer layers. Thecombination of spunbond and meltblown layers with either one containingan elastomeric polymer is preferred to allow the use of under-bondedwebs with higher extensibility during activation.

It is another object of the invention to create a stretchable multilayerfabric or substrate that can be thermally bonded more effectively viathe incorporation of at least one lower melting elastomeric material inat least one of the outer layers. Of particular interest are stretchlaminates that outperform current ones in their ability to form seamsover the very short amounts of time experienced in sealing operations athigh line speeds.

It is another object of the invention to provide more than one machinedirection activation step to expand and fine-tune the range of stretchin either or both outer layers prior to or after the lamination process.

It is a further object of the invention to have at least one machinedirection activation step on the stretchable multilayer fabric orsubstrate shortly after its assembly.

It is another object of the invention to have at least one machinedirection activation step on the stretchable multilayer fabric orsubstrate prior to the one or several machine direction activationsteps. The bonding patterns may be selected among a group capable ofproviding controlled apertures.

It is another object of the invention to provide a stretchablemultilayer fabric or substrate that can expand in directions in additionto the machine direction with the use of multidirectional activationprocesses. These processes enable the local reorientation of the strandsin part of the stretchable multilayer fabric or substrate as well as thedimensional growth of the fabric in directions other than the machinedirection.

It is another object of the invention to provide a stretchablemultilayer laminate with a gradient in stress profile and in the amountof gathering across its width.

It is another object of the invention to provide the use of thestretchable multilayered fabric or substrate in chassis components of adisposable absorbent product, whether as part of a stretchableoutercover or of a belted structure.

It is a further object of the invention to provide a process forcreating a stretchable multilayered fabric or substrate designed toimprove visual and tactile appeal while lowering material usage.

It is an object of this invention to provide a process that enables thecreation of a stretchable multilayered fabric or substrate with regionsof different performance and appearance across the width and thereforecapable of being used in different components of a belted stretchablechassis structure.

It is ultimately the object of the invention to provide a stretchablemultilayer fabric or substrate that uses overall less material, whetherin the strands content, in the basis weight of the outer layers, or theamount of adhesive needed.

Elastic Strands

Strands used in current “live stretch” laminates are typically made ofpolyester-polyurethane copolymer and are referred to by trade names suchas Lycra. Other suitable examples include styrenic block copolymers andelastomeric polyolefins, in particular formulations rich in elastomericpolypropylene. In these materials, propylene represents the majoritycomponent of the polymeric backbone, and as a result, any residualcrystallinity possesses the characteristics of polypropylene crystals.Residual crystalline entities embedded in the propylene-basedelastomeric molecular network may function as physical crosslinks,providing polymeric chain anchoring capabilities that improve themechanical properties of the elastic network, such as high recovery, lowset and low force relaxation. Suitable examples of elastomericpolypropylenes include an elastic random poly(propylene/olefin)copolymer, an isotactic polypropylene containing stereoerrors, anisotactic/atactic polypropylene block copolymer, an isotacticpolypropylene/random poly(propylene/olefin) copolymer block copolymer, astereoblock elastomeric polypropylene, a syndiotactic polypropyleneblock poly(ethylene-co-propylene) block syndiotactic polypropylenetriblock copolymer, an isotactic polypropylene block regioirregularpolypropylene block isotactic polypropylene triblock copolymer, apolyethylene random (ethylene/olefin) copolymer block copolymer, areactor blend polypropylene, a very low density polypropylene (or,equivalently, ultra low density polypropylene), a metallocenepolypropylene, and combinations thereof. Suitable polypropylene polymersincluding crystalline isotactic blocks and amorphous atactic blocks aredescribed, for example, in U.S. Pat. Nos. 6,559,262, 6,518,378, and6,169,151. Suitable isotactic polypropylene with stereoerrors along thepolymer chain are described in U.S. Pat. No. 6,555,643 and EP 1 256 594A1. Suitable examples include elastomeric random copolymers (RCPs)including propylene with a low level comonomer (e.g., ethylene or ahigher α-olefin) incorporated into the backbone. Suitable elastomericRCP materials are available under the names Vistamaxx (available fromExxonMobil, Houston, Tex.) and VERSIFY (available from Dow Chemical,Midland, Mich.), and may include a fraction of a higher crystallinitypolypropylene. An example of such a polypropylene is MFR 300. The ratioin some embodiments is about 90% to about 100% Vistamaxx, in othersabout 95% to about 100% Vistamaxx, and in still others about 97% toabout 100%.

Bi-component strands are preferred to ensure anti-blocking with alow-crystallinity polyethylene-based formulation in the outerlayer thatis called the sheath, coextruded with a very low-crystallinityelastomeric polypropylene that forms the core. Preferred lowcrystallinity polyethylene formulations include those described in USPatent Publication 2007/0287348, Autran, et al., assigned to P&G.

Some embodiments include strands made of a core made of about 90% toabout 99% of an elastomeric polypropylene formulation that includes amajority of Vistamaxx and a sheath made of about 1% to about 9% of apolyethylene formulation. Other embodiments may have a core of about 92%to about 98% of an elastomeric polypropylene formulation and still otherembodiments may have from about 95% to about 99%.

Other suitable commercially available polymers suitable for use aselastic strands include KRATON (styrenic block copolymer; available fromthe Shell Chemical Company, Houston, Tex.), SEPTON (styrenic blockcopolymer; available from Kuraray America, Inc., New York, N.Y.), VECTOR(styrenic block copolymer; available from Dexco Chemical Company,Houston, Tex.), ESTANE (polyurethane; available from Noveon, Inc.,Cleveland, Ohio), PEBAX (polyether amide; available from AtofinaChemicals, Philadelphia, Pa.), and HYTREL (polyester; available fromDuPont, Wilmington, Del.).

The elastic strands of the present invention may be prestrained prior tobeing assembled into laminates in order to maximize stretch/recovery.

For strand application, strand DTex (weight in gms per 10000 linearmeter) can vary. Strand DTex ideal for application can be decided byamount of force the laminate needs to exert. Commonly available Spandexin the DTex range between 400 and 1900 can be employed to provide theright fit. Each Spandex strand comes wound on bobbin. The length of eachspandex on bobbin is decided by the weight of the bobbin that processcan handle. Bobbins are mounted on OETO (over end take off) or RTO.

Strand Dtex (gms per Strand Strand localized 10000 linear meter)Diameter (mm) BW (gsm) 540 0.2404 224.7 680 0.2697 252.1 800 0.2925273.5 1150 0.3508 327.9 1200 0.3583 334.9 Spacing between Strand Dtex(gms per two strands Wt. Equivalent 10000 linear meter) (center tocenter) Elastic Film (gsm) 540 7 7.46 680 7 9.35 800 7 10.97 1150 715.64 1200 7 16.31

During the process of making a laminate, each individual strand isunwound from bobbin, and stretched to desired strain. The stretchedstrand is bonded to the nonwoven(s) or outer layers via adhesive,thermal bonding, ultrasonic bonding or any other bonding methodavailable. For adhesive bonding process, the adhesive is either appliedon strands or outer layer before combining. Ultrasonic or thermalbonding is carried out in a way that strand gets locked by selectivebonding of outer layers. Bonded Strands as laminate go throughactivation process described below.

Outer Stretchable Elastic Layers

The outer layers that may surround the elastic strands on both sides mayinclude two types:

1. Multilayer elastic nonwoven structures. These are layers that containelastic fibers. These may be combined with plastic fibers in single ormultiple layer structures. The size of a layer ranges from thattypically produced in spunbond and meltblown processes, that is, fromabout 10 to about 40 microns for the former and from about 0.5 to about5 microns for the latter. Spunbond fibers are preferred for theirstrength and durability, whereas opacity, toughness, and improvedprintability are imparted by incorporating one or several meltblownlayers. These are preferably formulated to provide at least partialelasticity and contain at least about 25% elastomeric polypropylene, orat least about 50%, or at least about 75%. The plastic spunbond fibershave an average diameter in the range of about 10 to about 40 microns orfrom about 15 to about 35 microns, or from about 15 to about 30 microns,and are made of polyolefins with polypropylene- and polyethylene-basedformulations found in a ratio from about 0 to about 100%. The fibers maybe either mono- or bi-component fibers.

Examples of the elastic nonwoven structures include SSM, SSMS or SSMMSnonwovens, which describe various ways of combining spunbond (S) andmeltblown (M) layers. The outerlayer spunbond layers are preferablyplastic-rich, meaning that the fibers represent the main components andare formulated to possess medium to high crystallinity polyolefins suchas polyethylene or polypropylene. These are preferably formulated andconstructed in a manner that favors their survivability duringmechanical activation and are referred to as extensible or highlyextensible spunbund nonwovens. Examples of such extensibles are found inprior granted U.S. Pat. Nos. 7,223,818, 7,776,771, and 8,182,456.Formulations may also include a fraction of an elastomeric polyolefinsuch as elastomeric polypropylene, and possibly a high MFR polypropylenecomponent. Extensibility in MD is preferred in this invention.

The inner layer of the multilayer outer layer is preferably anelastic-rich combination of spunbond and meltblown layers. It is alsopossible to have one of several spunbond and meltblown layers made of amixture of elastic and plastic fibers as disclosed in PatentApplications US2007287348, US2007287982, and US2007287983. At least oneof the meltblown layers may be made of low diameter fibers prepared viaa meltblown process and may contain at least one elastomeric polyolefin(VISTAMAXX from ExxonMobil, INFUSE from Dow, VERSIFY from Dow). Thepresence of several meltblown layers contributes to building upfilm-like properties and providing benefits such as opacity and barrierto adhesive among other features. The layer or layers with the smallerdiameter fibers may also include so called nanofibers with sub-microndiameter. The total basis weight of the elastic nonwoven structure isfrom about 30 gsm to about 120 gsm, or from about 30 to about 100 gsm,with the elastic fibers being from about 20 to about 70 gsm, and theplastic fibers from about 10 to about 50 gsm. Examples of multilayerfiber structures are disclosed in prior Patent ApplicationsUS2007287348, US2007287982, and US2007287983. The fiber assembly ismechanically activated to release its stretch/recovery features. Variousset-ups may be used and provide different scenarios of accomplishingthis objective. The benefits of having an elastomer-based meltblownlayer are to ensure its survivability during mechanical activation andto avoid extensive shredding, but also to ease the bonding between allthe layers by lowering the bonding temperature to significantly lowertemperatures. This opens up the possibility of underbonding the spunbondfiber assembly, which induces less fiber damage at bond sites, which inturn is known to promote higher extensibility in both MD and CD duringthe activation process. The final laminate would preferably be subjectedto more extensive thermal bonding further down the laminate assemblyline to ensure complete integrity.

2. Film/nonwoven stretchable elastic bilaminate structures. Thesecomprise various combinations of extruded elastic films with nonwovens.Again, the nonwovens are selected to exhibit highly extensibility in MDactivation. Optionally the nonwovens may also include some elasticcomponent as described before. However, the elasticity in designed tooriginate for the most part from the film itself. Examples of films andbilaminates have been described extensively in prior granted U.S. Pat.Nos. 8,445,744 and 8,168,853. In this invention thin elastic films arecreated with a variety of resins combined in at least one of severalsublayers, the latter providing different benefits to the film. Theelastic film is preferably polyolefin-based, more preferably elastomericpolypropylene-based. The laminates are preferably low-cost extruded oneswith little or no adhesive. One key feature in these bilaminates is forthe film to have a skin layer to prevent blocking. The total basisweight of the laminate is from about 20 gsm to about 80 gsm, or fromabout 25 gsm to about 70 gsm, or from about 25 gsm to about 60 gsm, withthe elastic film from about 10 gsm to about 40 gsm and the nonwoven fromabout 10 gsm to about 40 gsm. These have shown to be extensible in bothMD and CD with about 60% to about 80% in the former and from about 120%to about 160% in the latter. There are several approaches to improve MDextensibility which are being disclosed. Because of tooth clearanceissues on ring rolls, mechanical activation in MD is more limited tolower depths of engagement (DOE's). Process options that increase therange of MD extensibility beyond that provided by a single set ofactivation rolls are disclosed below. Underbonding the nonwoven maycontribute to increasing the MD extensibility of the bi-laminate. Othermeans of increasing MD extensibility can be created by allowing eitheror both nonwoven fiber reorientation and/or nonwoven fiber deformationduring the bi-laminate stretching process.

Stretchable Multilayer Fabric or Substrate

The stretchable multilayer fabric or substrate is created by assemblingthe inner layer comprising the elastic strands with at least one outerelastic layer. In one embodiment, the outer layer is only present on oneside of the strand, the other side consisting of a non-elastic nonwoven.In another embodiment, both sides are made with elastic outer layers.

In one embodiment, at least one side is made of a film/nonwoven-basedbilaminate. A small amount of adhesive in the range of from about 1 gsmto about 10 gsm, or from about 1 gsm to about 5 gsm, may be used to bondthe strands to the outer layers, with only low levels needed when bothstretchable outer layers are chosen to be film/nonwoven bilaminates.Thermal or Ultrasonic bonding may be used.

There are at least two processes for assembling the inner layercomprising strands with an outer layer in order to construct the finalassembly. One way is to first subject the outer layer to an activationprocess in the machine direction. The outer layer may then be strainedto some predetermined value prior to being brought in contact with theprestrained inner layer and bonded together (FIGS. 6A-6C). Another wayis to first combine the outer layer and the inner layer together andthen subject the assembly to activation in the machine direction (FIGS.8A-8C). These two processes are discussed in more detail below.

As FIGS. 6A and 6B illustrate, in the first option, the process consistsof subjecting each of the inner layer, 601 and the outer layer 602 toprestraining separately, FIG. 6A showing their length before stretching,and FIG. 6B depicting their length after stretching. The outer layer maybe subjected to an activation process in the machine direction in orderthe release the stretch in that particular direction. There are twomeans of increasing the range of the available strains in this processwhile limiting the amount of damage produced in the nonwoven; (i) takingthe outer layer through several successive activation units whilemaintaining some amount of prestrain between at least one contiguous setof units; or (ii) pre-activating the outer layer in the cross directionto pre-align the nonwoven fibers in the cross direction, hence providingmore room for the fibers to subsequently orient in the machinedirection. When several sets of rolls are used, it is also possible toheat up the web by contact against the first set of rolls, henceimproving the deformability of the nonwoven webs.

The outer layer can be strained to some predetermined length, 603, andthen brought in contact with the prestrained inner layer strands, 604,and adhesively bonded, resulting in the inner and outer layer assembly,605, as shown in FIG. 6C. Preferred adhesive patterns are those thathave the adhesive filaments oriented in the machine direction.

There are several scenarios for how much gathering, or puckering,ultimately results once the absorbent article is assembled, dependingupon the relative values of the strain in the outer layer versus that ofthe inner layer. In FIG. 6B, the strain of the stretched outer layer 603can be denoted as ε_(b), and defined as ε_(b)=(L_(b)−L_(o))/L_(o), whereL_(o) is the original length of the outer layer, 601, and L_(b) is thestretched length of the outer layer, 603. The strain of the stretchedinner layer, 604, is denoted as ε_(s), and defined byε_(s)=(L_(s)−L_(o))/L_(o), where L_(o) is the original length of theinner layer, 602, (same original length as for the outer layer), andL_(s) is the stretched length of the inner layer, 604.

The spectrum of scenarios shown in FIGS. 7A-7C reflects the assembly inthe relaxed state, with variations in the differential between therelative values of the strains, referred to as (ε_(s)−ε_(b)). In thefirst case, FIG. 7A, the strain ε_(b) of the outer layer, 701, isvirtually equal to zero. The outer layer, 701, has no recovery, whilethe inner layer, 702, does, ε_(s). This most closely resembles the typeof construction obtained in the current assembly where nonwovens formthe outer layer instead of the bilaminate used in this invention. Justas with a nonwoven outer layer, the outer layer has no recovery, andthis results in a substantial amount of puckering that can be observedupon recovery of the complete assembly, as the outer layer gathers tocomply with the retraction of the inner layer strands.

Puckering is the physical state used to describe the expansion of theassembly in the direction perpendicular to the plane. That is, asubstrate may be defined as primarily two-dimensional, in the x-y plane.Similarly, any of the layers, such as an outer layer or an inner layer,or even the assembly of inner and outer layers, may still primarily bedefined as two-dimensional, in the x-y plane. But when puckering occurs,that is, when one layer has greater strain than the strain of anotherlayer to which it is bonded, the assembly may expand in the z-direction.

In the second scenario and at the opposite extreme, as depicted in FIG.7B, ε_(b)=ε_(s), thus ε_(s)−ε_(b)=0, and the outer layer, 703, undergoescomplete recovery along with the inner layer, 704. In this instance nopuckering can be expected. Moreover the outer layer fully contributes tothe overall stretch performance profile. By doing so, it opens up thepossibility of reducing the number of strands necessary to achieve thestretch requirements of a given product design.

A continuum of scenarios exist that correspond to intermediate values of(ε_(s)−ε_(b)), which are depicted in FIG. 7C, where the outer layer,705, has partial recovery, so when combined with the inner layer 706,some visible puckering occurs. The larger the differential the morepuckering is observed. This is of great value as it offers a means oftailoring the aesthetics of the assembly and by extension that of theouter cover and this is of great value to the design of disposableabsorbent products.

The second option for the process to assemble the inner and outerlayers, as illustrated in FIGS. 8A-8C, consists in first taking theouter layer, 801, and the inner layer, 802, and creating the outer layerand inner layer assembly, 803, prior to subjecting the combined layersto activation in the machine direction, resulting in the stretchedassembly, 804. As always, the process releases the stretch in thatspecific direction. The use of an adhesive is preferred to hold theouter layer onto the inner layer, with preferred adhesive patterns asthose that have the adhesive layout of glue strings oriented in themachine direction.

As in the first processing option, in which the layers may beprestrained separately then joined, when the layers are first joined andthen strained, there are two means of increasing the ultimate range ofstrains produced in the final assembly while limiting the amount ofdamage done to the nonwoven; (i) taking the outer layer through severalactivation units while maintaining some amount of prestrain between atleast one set of contiguous units; or (ii) pre-activating the outerlayer/inner layer assembly in the cross direction to pre-align thenonwoven fibers in the cross direction, hence providing more slacks forthe fibers to subsequently orient in the machine direction. When severalsets of rolls are used, it is also possible to heat up the web bycontact against the first set of rolls, hence improving thedeformability of the nonwoven webs.

The spectrum of constructions that are created that reflect thepotential between the intrinsic type of recovery of the inner layer vs.that of the outer layer are the essentially the same for the secondprocess as for the first. That is, FIG. 7A depicts the one extremescenario, where ε_(b), the strain of the outer layer 801 when stretched,is nothing, ε_(b)=0, and there is maximum puckering, as the outer layerdoes not virtually recover at all. FIG. 7B depicts the other extremescenario, where ε_(b)=ε_(s), the outer layer strain roughly equals theinner layer strain, and no puckering occurs. The recovery of the outerlayer matches that of the inner layer, and there is no expansion of theouter layer in the z-direction, perpendicular to the plane. FIG. 7Cdepicts a range of intermediate scenarios that fall between thosedepicted in 7A and 7B, with the outer layer having plastoelasticdeformation profiles, where plasticity and elasticity are combined inresponse of the application of a strain: the more plasticity, the morepuckering.

Another processing option simply combines both the first and secondoptions discussed above, where part of the assembly construction is madewith the prestrained outer layer, while the other is made via machinedirection activation of the readily made one. Benefits may come fromdistributing the activations.

Tensile stress-strain curves can vary for the different constructionscenarios, wherein the amount of puckering determines the point wherethe laminates start to contribute to the overall loading curve whichadds up to that of the strands.

For both the first and second processing options, breathability may bean important attribute to the assembly. In the case where stretchelastic nonwoven form the outer layer, no special process is needed. Inthe scenario where a film is used, breathability may be achieved eitherby applying the well-known methods of dispersing calcium carbonateparticles in the film formulation that create micro-pores uponstretching, or, alternatively, by ensuring that slits or holes arepresent within the final assembly. The slits may be either discrete orextend continuously along the machine direction. Vacuum forming processcan be used to make apertures in the film or outer layer. It isconceivable that a combination of stretch nonwoven and full elastic filmor alternatively film strips may be constructed to form the outer layer.

Modes and Patterns of Mechanical Activation

The activation processes may be implemented through different scenarios.Variables may include the number of activation processes, their orders,and the locations by which they are applied onto the webs in order torelease the right amount of stretch. The latter correlates with thedepth of engagement (DOE) selected between interdigitated rolls. In allcases, the external layers are both activated in the machine direction(MD) to the maximum DOE possible using at least one set of activationrolls. Several sets of rolls may be mounted in series to release greaterextensibility. The preferred execution is to arrange for a differentrelative positioning of the set of rolls so that the peaks and valleysof the interdigitated rolls match different segments of the web. Inother words, web segments that were stretched between tooth lockedunstretched segments are to be positioned to not stretch between thesecond set of rolls.

In a different scenario, the second set of rolls rotates at a higherspeed than the first set of rolls, thus creating some MD strain on theweb as it enters the second set of rolls. The amount of activationtherefore compounds the first one, resulting in a greater amount of theoverall activation.

Multilayer films, laminates, and substrates of the present invention maybe mechanically activated by one or a combination of activating means,including, activating the web through intermeshing gears or plates,activating the web through incremental stretching, activating the web byring rolling, activating the web by tenter frame stretching, andactivating the web in the machine direction between nips or roll stacksoperating at different speeds. Incremental stretching rollers may beused to activate multilayer films and laminates in the MD, CD, at anangle, or any combination thereof. In some embodiments, the depth ofengagement used for incremental stretching is about 0.05 inches, about0.10 inches, about 0.15 inches, about 0.20 inches, or about 0.25 inches.The depth of engagement can be, for example, at least about 0.05 inchesor at least about 0.10 inches. The depth of engagement can be, forexample, no more than about 0.10 inches, no more than about 0.18 inches,or no more than about 0.25 inches. The pitch of engagement can be, forexample, from about 0.060 inches to about 0.200 inches, from about 0.080inches to about 0.150 inches, or from about 0.100 inches to about 0.125inches. Further, laminates may be activated at commercial rates via, forexample, the ring rolling activation process. The activation may occurimmediately after the lamination process or may occur as the laminate isunwound from a roll on which it was stored.

Absorbent Articles

FIG. 1 is a perspective view of an absorbent article 20. FIG. 2 is aperspective view of an absorbent article 20. The absorbent article 20has a longitudinal centerline L1 and a transverse centerline T1 (referto FIG. 3 as well). The absorbent article 20 has an outer surface 22, aninner surface 24 opposed to the outer surface 22, a front region 26, aback region 28, a crotch region 30, and seams 32 which join the frontregion 26 and the back region 28 to form two leg openings 34 and a waistopening 36. Also referring to FIGS. 2 and 3 , the absorbent article 20comprises a main portion 1, a side portion 2, and a waist portion 3.

In the embodiment shown in FIGS. 1 and 3 , the absorbent article 20comprises an absorbent main body 38 (hereinafter may be referred to as“main body”) to cover the crotch region of the wearer and a belt 40extending transversely about the waist opening 36. The absorbent article20 may also comprise an outer cover layer 42 to cover the main body 38.The belt 40 defines the waist opening 36. The belt 40, the main body 38and/or the outer cover layer 42 jointly define the leg opening 34. Theabsorbent article 20 may have a patch sheet 44 printed with a graphic 46thereon, which may be disposed in the front region 26 and/or the backregion 28. Throughout, it is understood that the terms “outer cover” and“backsheet” may be used interchangeably.

The multi-layer substrates described herein may be used in an outercover and/or may be used in a belt. That is, the materials described maybe used in any outer layer of the articles described, whether referredto as an outer cover and/or a belt. It may also be considered, in someembodiments, that the outer cover includes the entire outer layer of thearticle, including a belt in some places in addition to non-belt placesin others.

In the embodiment shown in FIG. 2 the absorbent article 20 comprises anabsorbent main body 38 to cover the crotch region of the wearer and abelt 40 extending transversely about the waist opening 36. The absorbentarticle 20 may also comprise an outer cover layer 42 to cover the mainbody 38. The belt 40 defines the waist opening 36. The belt 40, the mainbody 38 and/or the outer cover layer 42 jointly define the leg opening34. One or more of the belt layers may extend from a first waist edge134 in a first waist region 26 through the crotch region to alongitudinally opposing second waist edge 138 in a second waist region28 and forming a portion of the outer surface of the absorbent article20.

The absorbent main body 38 absorbs and contains body exudates disposedon the main body 38. In the embodiment shown in FIG. 3 , the main body38 has a generally rectangular shape having a longitudinal centerlineL1, a transverse centerline T1, left and right longitudinally extendingside edges 48 (hereinafter may be referred to as “longitudinal sideedge”) and front and back transversely extending end edges 50(hereinafter may be referred to as “transverse end edge”). The main body38 also has waist panels (i.e., a front waist panel 52 positioned in thefront waist region 26 of the absorbent article 20 and a back waist panel54 positioned in the back waist region 28) and a crotch panel 56 in thecrotch region 30 between the front and back waist panels 52, 54.

In the embodiment shown in FIGS. 4 a and 4 b , the absorbent articles 20may comprise front and rear belts 84, 86 intended to encircle at least aportion of the waist of the wearer, the front and rear belt portions 84,86 being connected by a main body 38 forming the crotch region 30 of theabsorbent article 20. The front and rear belts 84 and 86 may be formedfrom a first belt layer forming a portion of the outer surface 22 of theabsorbent article, the first belt layer 82 may be formed of twolongitudinally spaced webs of material. The front and rear belts 84 and86 may also comprise a second belt layer 83 forming a portion of theinner surface 24 of the absorbent article 20, the second belt layer 83may also be formed of two longitudinally spaced webs of material. Thesecond belt layer may also be discontinuous and spaced apart in atransverse direction. The first and second belt layers 82, 83 may beformed of substantially the same material or may comprise differentmaterials. The first and second belt layers 82, 83 may be formed fromnonwovens, films, foams, elastic nonwoven, or combinations thereof. Thefront and rear belts 84, 86 may also comprise an elastomeric materialdisposed between the first and second belt layers 82, 83. Theelastomeric material may comprise one or more elastic strands,elastomeric films, elastomeric ribbons, elastomeric nonwovens,elastomeric filaments, elastomeric adhesives, elastomeric foams, scrimsor combinations thereof. A portion of the elastomeric material may bedirectly combined with the outer cover layer. The main body 38 of theabsorbent article may comprise an outer surface 22, backsheet 60, aninner surface 24, topsheet 58, an absorbent core 62 disposed between thetopsheet 58 and the backsheet 60, and an outer cover 42. The backsheetmay be formed of a nonwoven material, woven material, films or laminatescomprising a combination of one or more of these materials. In oneembodiment the backsheet is a film and nonwoven laminate wherein thenonwoven of the laminate is the outer cover layer. In addition, the mainbody 38 may comprise elasticized barrier leg cuffs 64 disposed at oradjacent the side edges of the main body. The front and rear belts 84,86 may overlap at least a portion of the main body and one or both ofthe belt portions may be disposed on the outer surface of the main bodyor alternatively on the inner surface of the main body. A portion of thesecond belt layer and/or a portion of the first belt layer may bedirectly attached to the outer cover layer. Alternatively, the frontbelt and rear belt 84, 86 may comprise longitudinally spaced webs ofmaterial forming a first surface of the belt wherein the webs are foldedalong the waist edge, or alternatively the leg opening edge, of the beltto wrap the elastomeric material and form at least a portion of thesecond surface of the belt. In other words, at least a portion of theinner surface and outer surface of each of the belt portions may beformed from a single web of material.

In the embodiment shown in FIGS. 4 c and 4 d , the absorbent articles 20may comprise front and rear extensible belts 84, 86 disposed in thefront and rear waist regions 26, 28 respectively and intended toencircle at least a portion of the waist of the wearer, the front andrear belts 84, 86 being connected by the main body that forms the crotchregion 30 of the article. The first and second belt may be formed from afirst belt layer extending from a first waist edge 134 in a first waistregion 26 through the crotch region to a longitudinally opposing secondwaist edge 138 in a second waist region 28 and forming a portion of theouter surface of the absorbent article 20. The front and rear belts 84,86 also may comprise a second belt layer 83 forming a portion of theinner surface of the absorbent article, the second belt layer may beformed of two longitudinally spaced webs of material. The first andsecond belt portions may also comprise an elastomeric material disposedbetween the first and second belt layers. The elastomeric material maycomprise elastic strands, elastomeric films, elastomeric ribbons,elastomeric nonwovens, elastomeric filaments, elastomeric adhesives,elastomeric foams, scrims or combinations thereof. The main body 38 ofthe absorbent article may comprise an outer surface 22, backsheet 60, aninner surface 24, topsheet 58, and an absorbent core 62 disposed betweenthe topsheet 58 and the backsheet 60. The first belt layer may form aportion of the outer surface 22. In addition, the main body may compriseelasticized barrier leg cuffs 64 disposed at or adjacent the side edgesof the main body. The second belt layer may overlap at least a portionof the main body and one or both of the second belt layer webs may formthe outer surface of the first belt layer or alternatively the innersurface of the first belt layer. Alternatively, the front portion and/orthe rear portion of the first belt layer may be folded along the waistedge of the belt region to wrap the elastomeric material and form aportion of the second belt layer of one or both of the front and rearbelt portions 84, 86. In other words, the inner surface and outersurface of each of the belt portions is formed from a single web ofmaterial.

In the embodiment shown in FIGS. 4 e and 4 f , the absorbent articles 20may comprise a full outer cover layer 42, extending from a front waistedge 134 in a first waist region 26, through the crotch region to thelongitudinally opposing rear waist edge 138 in a second waist region 28.The article may also comprise front and rear belts 84, 86 intended toencircle the waist of the wearer, the front and rear belts 84, 86 beingconnected to the outer cover layer 42 and/or the main body 38 of theabsorbent article 20. The first and second belts are formed from a firstbelt layer forming a portion of the outer surface of the belt, the firstbelt layer being formed of two longitudinally spaced webs of material.The first and second belt portions also comprise a second belt layerforming a portion of the inner surface of the absorbent article, thesecond belt layer also being formed of two longitudinally spaced webs ofmaterial. The first and second belt layers may be formed ofsubstantially the same material or may comprise different materials. Thefirst and second belt layers may be formed from nonwovens, films, foamsor combinations thereof. The first and second belts may also comprise anelastomeric material disposed between the first and second belt layers.The elastomeric material may comprise elastic strands, elastomericfilms, elastomeric ribbons, elastomeric nonwovens, elastomericfilaments, elastomeric adhesives, elastomeric foams, scrims orcombinations thereof. The first and second belts may be disposed on theinterior surface of the outer cover layer. Alternatively, the first andsecond belts may be disposed on the outer surface of the outer coverlayer. In such an embodiment the outer cover layer would for a portionof the inner surface of the article in the waist regions and the firstbelt layer would form a portion of the outer surface of the article. Thesecond belt layer when present may be disposed between the first beltlayer and the outer cover layer. The main body 38 of the absorbentarticle 20 may comprise an outer surface 22, backsheet 60, an innersurface 24, topsheet 58, and an absorbent core 62 disposed between thetopsheet 58 and the backsheet 60. In addition, the main body 38 maycomprise elasticized barrier leg cuffs 64 disposed at or adjacent theside edges of the main body 38. One or both of the front and rear belts84, 86 may overlap at least a portion of the main body 38 and one orboth of the belts may be disposed on the outer surface of the main body38 or alternatively on the inner surface of the main body 38. One orboth of the front and rear belts 84, 86 may be disposed on the interiorsurface of the outer cover layer or alternatively one or both of thebelts may be disposed on the exterior surface of the outer cover layer.One or both of the front belt and rear belt 84, 86 may compriselongitudinally spaced webs of material forming a first surface of thebelt wherein the webs are folded along the waist edge 36 of the belt towrap the elastomeric material and form at least a portion of the secondsurface of the belt. In other words, a portion or the entirety of theinner surface and outer surface of one or both of the belt portions maybe formed from a single web of material. The rugosities, wrinkles, foldsin one or both of the front and rear belts may have a differentconfiguration, size, orientation, shape, etc. than that of the outercover layer.

In the embodiment shown in FIG. 4 g , the absorbent articles 20 maycomprise front and rear belts 84, 86 intended to encircle at least aportion of the waist of the wearer, the front and rear belts 84, 86being connected to a main body 38 forming a portion of the crotch region30 of the absorbent article 20. The front and rear belts 84, 86 areformed from a first belt layer forming a portion of the outer surface ofthe absorbent article. The front and rear belt portions 84, 86 alsocomprise a second belt layer 83 forming a portion of the inner surface24 of the absorbent article 20. The second belt layer may be laterallydiscontinuous and spaced apart in a transverse direction. The first andsecond belt layers 82, 83 may be formed of substantially the samematerial or may comprise different materials. The first and second beltlayers 82, 83 may be formed from nonwovens, films, foams or combinationsthereof. The front and rear belt portions 84, 86 may also comprise anelastomeric material disposed between the first and second belt layers82, 83. The elastomeric material may comprise elastic strands,elastomeric films, elastomeric ribbons, elastomeric nonwovens,elastomeric filaments, elastomeric adhesives, elastomeric foams, scrimsor combinations thereof. A portion of the elastomeric material may bedirectly combined with the outer cover layer. The main body 38 of theabsorbent article may comprise an outer surface 22, backsheet 60, aninner surface 24, topsheet 58, and an absorbent core 62 disposed betweenthe topsheet 58 and the backsheet 60. In certain embodiments thebacksheet may be a nonwoven and film laminate wherein the nonwoven isformed by the outer cover layer. In addition, the main body 38 maycomprise elasticized barrier leg cuffs 64 disposed at or adjacent theside edges of the main body 38. The front and rear belts 84, 86 overlapat least a portion of the main body 38 and one or both of the belts maybe disposed on the outer surface of the main body 38 or alternatively onthe inner surface of the main body 38. A portion of the second beltlayer and/or a portion of the first belt layer may be directly attachedto the outer cover layer. The front and rear belts 84, 86 may be formedfrom a first belt layer extending from a first waist edge 134 in a firstwaist region 26 through the crotch region to a second waist edge 138 ina second waist region 28 and forming a portion of the outer surface ofthe absorbent article 20. The front and rear belts 84, 86 may alsocomprise a second belt layer extending from a first waist edge 134 in afirst waist region 26 through the crotch region to a second waist edge138 in a second waist region 28 and forming a portion of the innersurface of the absorbent article 20. The first and second belt layersmay be formed of substantially the same material or may comprisedifferent materials. The first and second belt layers may be formed fromnonwovens, films, foams, woven materials or combinations thereof. Thefront and rear belt portions 84, 86 may also comprise an elastomericmaterial disposed between the first and second belt layers in one orboth of the first and second waist regions 26, 28. The elastomericmaterial may comprise elastic strands, elastomeric films, elastomericribbons, elastomeric nonwovens, elastomeric filaments, elastomericadhesives, elastomeric foams, scrims or combinations thereof. The mainbody 38 of the absorbent article 20 may comprise an outer surface 22,backsheet 60, an inner surface 24, topsheet 58, and an absorbent core 62disposed between the topsheet 58 and the backsheet 60. One or both ofthe first and second belt layers may form a portion of the outer surface22. In addition, the main body 38 may comprise elasticized barrier legcuffs 64 disposed at or adjacent the side edges of the main body 38. Aportion of one or both of the front and rear belts 84, 86 may overlap atleast a portion of the main body 38. Alternatively, the front beltportion and rear belts 84, 86 may comprise a belt layer forming a firstsurface of the belt portion wherein the belt layer may be folded alongthe waist edge of the belt portion to wrap the elastomeric material andoverlap a portion of the opposing belt layer. In other words, a portionof the inner surface and a portion of the outer surface of each of thebelt portions may be formed from a single web of material.

The main body 38 may comprise a liquid pervious topsheet 58, a liquidimpervious backsheet 60 and an absorbent core 62 disposed therebetween.The main body 38 may additionally comprise a barrier leg cuff 64disposed along the longitudinal side edge 48. The barrier leg cuff 64provides improved containment of liquids and other body exudates in thecrotch region 30. The barrier leg cuff 64 shown in FIG. 5 comprises asingle layer of material which may be folded to form a barrier leg cuffhaving two layers. The barrier leg cuff 64 extends from the side of themain body at or adjacent the longitudinal side edge 48 toward thelongitudinal centerline L1. The barrier leg cuff may be folded along thefolding line 66 back toward the longitudinal side edge 48. The barrierleg cuff 64 may have a first barrier cuff elastic material 72 adjacentto the distal portion 68 and a second barrier cuff elastic material 73adjacent to the proximal portion 70 of the barrier leg cuff 64. Theproximal portion 70 of the barrier leg cuff 64 may be joined to thebacksheet 60 adjacent to the longitudinal side edge 48. The portion ofthe barrier leg cuff 64 along the folding line 66 and the distal portion68 may be free from attachment to any portion of the main body 38 in thecrotch region 30 such that the barrier leg cuff 64 stands up toward thewearer's body. The transverse end 74 of the barrier leg cuff 64 may bejoined to the topsheet 58 at or adjacent the longitudinally opposingends of the leg cuff by an attachment means which may be any known meanssuch as an adhesive, heat bond, pressure bond or the like as shown in 5.

The liquid pervious topsheet 58 may be positioned adjacent thebody-facing surface of the absorbent core 62 and may be joined theretoand/or to the backsheet 60 by any attachment means known in the art. Theliquid impervious backsheet 60 is generally that portion of theabsorbent article 20 positioned adjacent the garment-facing surface ofthe absorbent core 62 and prevents the exudates absorbed and containedtherein from soiling articles that may contact the absorbent article 20.The absorbent core is positioned between the topsheet 58 and thebacksheet 60 and absorbs and retains liquids such as urine and othercertain body exudates.

The topsheet 58, the backsheet 60 and the absorbent core may bemanufactured any known materials. Suitable topsheet materials mayinclude porous foams; reticulated foams; apertured plastic films; orwoven or nonwoven webs of natural fibers (e.g., wood or cotton fibers),synthetic fibers (e.g., polyester or polypropylene fibers), or acombination of natural and synthetic fibers. Suitable backsheetmaterials may include breathable materials that permit vapors to escapefrom the diaper while still preventing exudates from passing through thebacksheet.

A suitable absorbent core for use in the absorbent article 20 maycomprise any absorbent material which is generally compressible,conformable, non-irritating to the wearer's skin, and capable ofabsorbing and retaining liquids such as urine and other certain bodyexudates. In addition, the configuration and construction of theabsorbent core may also be varied (e.g., the absorbent core(s) or otherabsorbent structure(s) may have varying caliper zones, hydrophilicgradient(s), a superabsorbent gradient(s), or lower average density andlower average basis weight acquisition zones; or may comprise one ormore layers or structures). In some embodiments, the absorbent core maycomprise a fluid acquisition component, a fluid distribution component,and a fluid storage component. An example of a suitable absorbent corehaving a fluid acquisition component, a fluid distribution component,and a fluid storage component is described in U.S. Pat. No. 6,590,136.

The outer cover layer 42 may be disposed on the outer surface 22 of theabsorbent article 20 and covers the crotch panel 56 of the absorbentmain body 38. The outer cover layer 42 may extend into and cover thefront waist panel 52 and the back waist panel 54 of the main body 38.The outer cover layer may form a portion of the backsheet and/or themain body. The outer cover layer 42 may be directly joined to and covera portion or all of the liquid impervious backsheet 60 of the main body38. The central panel 80 of the front and back belt 84, 86 may be joinedto the front waist panel 52 and the back waist panel 54 of the main body38 through the outer cover layer 42. Thus, the outer cover layer 42 isdisposed between the front and back belt 84, 86 and the liquidimpervious backsheet 60 of the main body 38. In one embodiment shown inFIGS. 2 and 4 c, the outer cover layer 42 is coextensive with the liquidimpervious backsheet 60. The leg elastic material 140 is disposed so asto extend generally longitudinally along the longitudinal side edge 48of the main body 38. The leg elastic material 140 may be disposed atleast in the crotch region 30 of the absorbent article 20 or may bedisposed along the entirety of the longitudinal side edge 48.

The outer cover layer 42 comprises a material separate from the materialof the inner layer 83 and the outer layer 82 constituting the belt 40.The outer cover layer 42 may comprise two or more layers of materials.The outer cover layer 42 may comprise any known materials and maycomprise materials used for the front and back belt 84, 86 as explainedabove. The outer cover layer 42 may comprise a single layer of nonwovenweb of synthetic fibers. The outer cover layer 42 may comprise a singlelayer of hydrophobic, non-stretchable nonwoven material. The outer coverlayer may comprise a film, a foam, a nonwoven, a woven material or thelike and/or combinations thereof such as a laminate of a film and anonwoven.

Test Method: 1. Basis Weight, Initial Tensile Test, and Hysteresis Test1-1. Sample Preparation

The direction in which the elastic laminate will stretch in its intendeduse is considered the primary stretch direction of the material. One setof rectilinear specimens at least 56 mm long in the primary stretchdirection, and 25.4 mm wide in the perpendicular direction is cut fromthe center portion of the product part. Articles having areas oflaminate smaller than 56×25.4 mm are considered to be outside the scopeof this method. Five specimens are cut from the same portion ofidentical products for each set. The basis weight of each specimen ismeasured. Each set is analyzed by the methods described below. For theTensile Test and Hysteresis Test, the direction in which specimen haslonger dimension is considered the specimen direction of stretching.

1-2. Specimen Weight and Basis Weight

Each specimen is weighed to within ±0.1 milligram using a digitalbalance. Specimen length and width are measured using digital Verniercalipers or equivalent to within ±0.1 mm. All testing is conducted at22±2° C. and 50±10% relative humidity. Basis weight is calculated usingequation below.

${{Basis}{Weight}\left( \frac{g}{m^{2}} \right)} = \frac{\left( {{Weight}{of}{the}{sample}{in}{grams}} \right)}{\left( {{Length}{of}{the}{sample}{in}{meter}} \right)\left( {{Width}{of}{the}{sample}{in}{meter}} \right)}$

1-3. Tensile Test Setup

A suitable tensile tester interfaced with a computer such as MTS modelAlliance RT/1 with TestWorks 4® software or equivalent is used. Thetensile tester is located in a temperature-controlled room at 22° C.±2°C. and 50±10% relative humidity. The instrument is calibrated accordingto the manufacturer's instructions. The data acquisition rate is set toat least 50 Hertz. The grips used for the test are wider than thesample. Grips having 50.8 mm width may be used. The grips are airactuated grips designed to concentrate the entire gripping force along asingle line perpendicular to the direction of testing stress having oneflat surface and an opposing face from which protrudes a half round(radius=6 mm, e.g. part number: 56-163-827 from MTS Systems Corp.) orequivalent grips, to minimize slippage of the sample. The load cell isselected so that the forces measured are between 10% and 90% of thecapacity of the load cell used. The initial distance between the linesof gripping force (gauge length) is set at 50.8 mm. The load reading onthe instrument is zeroed to account for the mass of the fixture andgrips.

The specimen is mounted into the grips in a manner such that there is noslack and the load measured is between 0.00 N and 0.02 N. The specimenis mounted in the center of the grips, such that the specimen directionof stretching is parallel to the applied tensile stress.

1-4. Tensile Test

The instrument is set up and the specimen mounted as described in theTensile Test Setup above. The tensile test is initiated and the specimenis extended at 508 mm/min, with a data acquisition rate of at least 50Hertz, until the specimen breaks, typically 500-1000% strain. The %strain is calculated from the length between grip lines L, and initialgauge length, L₀, as illustrated in FIG. 6A, using the followingformula:

${\%{Strain}} = {\frac{\left( {L - L_{0}} \right)}{L_{0}} \times 100}$

Rupture or breakage is defined as sudden drop in force with smallincrease in strain. For all samples, Force at 130% strain, Force atbreak, and % Strain at break are reported.

1-5. Hysteresis Test

The instrument is set up and the specimen mounted as described in theTensile Test Setup section above, except the gauge length is reduced to25.4 mm. Data acquisition rate is set to at least 50 Hertz.

The Hysteresis Test method for film specimens involves the followingsteps (all strains are % strains):

(1) Strain the specimen to 50% strain at a constant crosshead speed of25.4 cm per minute.(2) Go to 0% strain at a constant crosshead speed of 25.4 cm per minute.(3) Pull the specimen to 0.127 N force and return to 0% strain with nohold time.Specimen length at 0.127 N force in step (3) is recorded and used tocalculate the % set in the material as below.

% Set=((Length at 0.127 N force−Original Gauge length)/Original Gaugelength))×100

Five specimens of each film set are measured, and the arithmetic averageis calculated for % Set.

The Percent Recovery is defined from % Set data.

Percent Recovery=100%−% Set.

Materials:

Elastomeric laminates of the present inventions are made using stretchbi-laminates, spandex elastic strands, and adhesive. The stretchbi-laminates are used as outer layer in the examples described below.They are prepared by extrusion lamination as described in patentapplications US 2009258210, US 2009264844, and US 2010040826. Thebi-laminate M20-0018-3B received from Clopay, USA is used. It is made byextrusion bonding 15 gsm bicomponent nonwoven to 20 gsm elastomericfilm. The bi-laminate is activated in machine direction usingincremental stretching process. Activation is carried out twice to 3 mmdepth of engagement with 2.49 mm activation pitch plate on HSRP (HighSpeed Research Press) machine as described in U.S. Pat. Nos. 7,062,983and 6,843,134 issued to Anderson et al. The bi-laminate material edgesin machine direction are held at the same place during dual activation.The dual activation releases 60% strain, i.e. 100 mm material stretchesto 160 mm, in the bi-laminate, before it hits force wall, i.e. steepincrease in force beyond 60% strain. Force wall is where there is steepincrease in force with small increase in % strain, i.e. slope greaterthan 0.1.

For inner layer, Spandex strands are used. Commercially available“Lycra” at 1100 dtex from INVISTA, USA is used as Spandex strands.Bonding of bi-laminate and strands is carried out using glue sprayed inspiral pattern at ˜ 6 gsm. H2861 glue, commercially available fromBostik, USA is sprayed on Silicone release paper to create glue sheetsthat can be used later to hand bond spandex strands to bi-laminates.

EXAMPLES Example 1

Activated bi-laminate cut in 220 mm long in machine direction and 30 mmwide in cross direction, and used as outer layers in the laminate.Bi-laminate in non-strained condition is taped down on flat solidsurface with film surface on the open side. Tapes are attached on MDedges of bi-laminate with 200 mm spacing between inside edges of tapes.Spiral glue sheet is applied on top of the film surface, and rolled withHR-100 ASTM roller before removing release paper off. Three spandexstrands spaced apart by 6-8 mm are taped at 100 mm distance, and used asinner layer. Strands are stretched 100% strain, i.e. 100 mm distancebetween tape edges stretches to 200 mm, and are laid over the open glueface of the laminate being made. Strand stretch direction is aligned tolaminate machine direction, and center strand is placed at 15 mm fromthe top edge of the laminate. Strands are held in the stretchedcondition using tapes at the edges. Another glue sheet is applied on topof the strands and rolled as before. Once, the release paper is removed,another bi-laminate is placed on top of the laminate. The secondbi-laminate of the same dimensions as the first bi-laminate, is alignedin Machine direction and cross-direction with the first bi-laminate.Whole laminate assembly is then rolled with HR-100 ASTM roller, andrelaxed to allow partial elastic recovery. When relaxed, outer layersadhered on top and bottom of the inner layer are gathered when innerstrand layer returns to their original positon. Example 1 representslaminate making described in FIG. 7A, where the strain in the ε_(b) ofthe outer layer bi-laminate, 701, is virtually equal to zero. The innerstrand layer has strain of 100%, which is ε_(s). The corrugations orpuckering is tight as the difference in strain (ε_(s)−ε_(b)) is high.

Example 2

Example 2 is made the same way as Example 1, except both bi-laminates,first and second, are strained to 60% before combining. When outerlayers made of bi-laminate are strained, i.e. ε_(b)=60%, and the innerlayer made of strands is strained to 100%, ε_(s)=100%, the (ε_(s)−ε_(b))value is 40%, in between minimum 0% and maximum 100%. This producesintermediate gathering as shown in FIG. 9 .

Example 3

Example 3 is made the same way as Example 1, except elastic strands arestretched to 150% before combining. The difference in strain,(ε_(s)−ε_(b)), is higher compared to Example 1. This results in tightergathering compared to Example 1 as shown in FIG. 9 .

Example 4

Example 4 is made the same way as Example 2, except elastic strands arestretched to 150% level before combining.

FIG. 9 shows Examples 1-4.

The four example materials were tested as per the Tensile Test describedabove. FIG. 10 shows Force (load)-Strain curve for Example 1 through 4.

Example 1 follows strand force profile until 90% strain, and thenfollows bi-laminate plus strand combined force profile until it hitsforce wall at around 180% strain. Although strands were strained to100%, only 90% strain is achieved in the final laminate as some of thestretch is lost due to resistance from outer layer gathering and gluelamination. The use of stretch bi-laminate instead of non-stretchsubstrate as outer layer however released additional 90% stretch out ofthe final laminate. This example shows that stretch level of thelaminate of present invention can be tailored by selective combinationof inner and outer layers, while keeping combining strain level duringlamination process lower.

Example 2 on the other hand was tailored to improve stress or forceprofile while keeping the laminate stretch level nearly the same as thecombining strain. The laminate of example 2 follows strand force profileup to 30% strain, although the strands were strained to 100% duringcombining. After 30% applied strain, the laminate follows bilaminateplus strand force profile as the force increases with the strain.Eventually at around 120% strain, the laminate hits force wall profile.Such force-strain profile of laminate helps improve product fit whendesired.

Example 3 and 4 are variation of Example 1 and 2, respectively. Example3 and 4 show little higher stretch level compared to Example 1 and 2.

The dimensions and values disclosed herein are not to be understood asbeing strictly limited to the exact numeral values recited. Instead,unless otherwise specified, each such dimension is intended to mean boththe recited value and a functionally equivalent range surrounding thatvalue. For example, a dimension disclosed as “40 mm” is intended to mean“about 40 mm”.

All documents cited in the Detailed Description of the Invention are, inrelevant part, incorporated herein by reference; the citation of anydocument is not to be construed as an admission that it is prior artwith respect to the present invention. To the extent that any meaning ordefinition of a term in this written document conflicts with any meaningor definition of the term in a document incorporated by reference, themeaning or definition assigned to the term in this written documentshall govern.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

What is claimed is:
 1. An absorbent article comprising: a topsheet; anouter cover; and an absorbent core disposed between the topsheet and theouter cover; wherein the outer cover comprises a multilayer substratecomprising: a first outer layer and a second outer layer, wherein atleast one of the first and second outer layers comprises a componentthat exhibits at least partial elastic recovery; an inner layer,disposed between the first outer layer and the second outer layer, theinner layer comprising elastic strands; and wherein at least one of thefirst outer layer and second outer layer is laminated to the innerlayer; wherein at least one of the first and second outer layerscomprises a film-nonwoven laminate; and wherein the film-nonwovenlaminate comprises a film comprising at least one elastomeric component.2. The absorbent article of claim 1, wherein the inner layer comprisingelastic strands is prestrained.